The purpose of this application is to request funding for a Cytomation desk top flow cytometer with sorting capability, and fitted with a device to protect the operator from aerosol exposure. The primary reason for this request is the realization that our existing instrument is obsolete, and whilst some modifications are still possible to software components, there is no longer any guarantee that failed mechanical parts can be replaced in the future. This instrument is a workhorse that has significantly helped us make major contributions to the field of infectious disease research under the auspices of severely highly visible and generously funded major NIH research programs at CSU. As a result, failure of the instrument will seriously impact a number of programs, including research into tuberculosis, vector borne viral diseases, and AIDS-associated opportunistic infections. Because of these level II and level III pathogens, regular clinical diagnostic instruments present at CSU cannot be used. The instrument will be housed in our new Level III BioEnvironmental Hazards building scheduled for completion in the Spring of 1999. As required, this proposal names a Users committee involving the primary Principal Investigators, an additional faculty member who is an internationally recognized expert in flow cytometry, and three senior members of the applicant's staff who will be responsible for the daily maintenance of the requested instrument. An estimate of usage by each group is also provided, based upon our experience with our current instrument.